JP2019104164A - Image recorder and image recording method - Google Patents

Abstract

To suppress unevenness of an image in a recorded matter even when a film thickness of a reaction liquid varies.SOLUTION: An image recording device 1 comprises: a transfer unit 4 having a transfer body 2 and an impression cylinder 42 for forming a nip part 11, and transferring an image of a recording liquid formed to the transfer body 2 to a recording medium P1 by the nip part 11; a recording unit 3 for forming an image of the recording liquid to the transfer body 2 by discharging the recording liquid; a reaction liquid applying unit 5A provided on a front stage of the recording unit 3, and forming a film of the reaction liquid for increasing viscosity of the recording liquid to the transfer body 2 in advance; a film thickness detector 12 for detecting a film thickness of the reaction liquid formed on the transfer body 2; and a control part 13B for determining whether or not to form an image of the recording liquid according to the film thickness, and determining whether or not to actuate the reaction liquid applying unit 5A based on the determination result.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image recording apparatus and an image recording method for recording on a recording medium by transferring an image of a recording liquid formed on a transfer body to the recording medium.

  As one of the ink jet recording methods, an image recording apparatus and an image recording method using a transfer body are known. Patent Document 1 discloses an image recording apparatus and an image recording method for recording on a recording medium by transferring an ink image formed on a transfer body to the recording medium. In order to increase the viscosity of the ink, a water absorbing setting agent made of powder is applied to the transfer body before forming the ink image on the transfer body. As a result, the ink becomes a gel-like substance having an appropriate viscosity.

Japanese Patent Application Laid-Open No. 2002-292852

Although the setting agent described in Patent Document 1 is a powder, a liquid for increasing the viscosity of the ink may be applied to the transfer body in advance. Such a liquid is referred to herein as a reaction liquid. The reaction liquid is a liquid, so application is easy, and it is also easy to make the film thickness uniform. However, since the reaction solution is usually applied by a roller or the like, it is difficult to make the film thickness of the reaction solution completely uniform. Although it is possible to control the coating amount to make the film thickness uniform, a mechanism for controlling the rotation of the roller is required, and the configuration is not cheap. For this reason, the film thickness of the reaction solution varies depending on the position of the transfer body. The variation in film thickness causes variation in the reaction between the reaction liquid and the ink droplets, resulting in unevenness of the image in the recorded matter.
An object of the present invention is to provide an image recording apparatus and an image recording method capable of suppressing unevenness of an image in a recorded matter even when variation in film thickness of a reaction liquid occurs.

  The image recording apparatus of the present invention has a transfer body forming a nip portion and an impression cylinder, and a transfer unit in which an image of the recording liquid formed on the transfer body is transferred to a recording medium at the nip portion, a recording liquid A recording unit that forms an image of the recording liquid on the transfer body, and a reaction liquid application unit that is located in front of the recording unit and forms a film of the reaction liquid on the transfer body in advance to increase the viscosity of the recording liquid. A detector that detects the film thickness of the reaction liquid film formed on the transfer body, and whether or not to form an image of the recording liquid according to the film thickness, determines whether to operate the recording unit based on the determination result And a control unit that determines

  The image recording method of the present invention performs recording on a recording medium by transferring the image of the recording liquid formed on the transfer body by the recording unit onto the recording medium. According to the present image recording method, a film of a reaction liquid for increasing the viscosity of the recording liquid is formed on the transfer body, a film thickness of the reaction liquid film formed on the transfer body is detected, and the film thickness is determined. Determining whether to form an image of the recording liquid, and determining whether to operate the recording unit based on the determination result.

  According to the present invention, whether or not to form an image of the recording liquid is judged according to the film thickness of the reaction liquid, and the recording unit is controlled based on the judgment result. Therefore, according to the present invention, even when the film thickness of the reaction liquid varies, it is possible to suppress the unevenness of the image in the recorded matter.

FIG. 1 is a schematic view of an image recording apparatus according to an embodiment of the present invention. It is a schematic block diagram of a control system of the image recording apparatus shown in FIG. It is a schematic block diagram of a control system of the image recording apparatus shown in FIG. It is explanatory drawing of the operation example of the image recording apparatus shown in FIG. It is a figure which shows the example of the application nonuniformity area | region and printing area | region in a transfer body. It is a flowchart which shows the image recording method which concerns on one Embodiment of this invention. It is a figure which shows an example of the output of a film thickness detector. It is a flowchart for detecting the nonuniformity of the film thickness of a reaction liquid. It is a figure which shows the other example of the application nonuniformity area | region and printing area | region in a transfer body.

  Several embodiments of the present invention will be described with reference to the drawings. First, the configuration and basic operation example of an image recording apparatus according to an embodiment of the present invention will be described. In each figure, arrows X and Y indicate horizontal directions and are orthogonal to each other. Arrow Z indicates the up and down direction. “Recording” in the present invention not only forms significant information such as characters and figures but also forms images, patterns, patterns, etc. widely on a recording medium regardless of significant meaninglessness and processing of the recording medium Including doing. The object to be "recorded" may or may not be manifested so that it can be perceived by humans. The “recording medium” is a sheet of paper in the present embodiment, but may be a cloth, a plastic film or the like. In the present embodiment, the substance formed on the transfer body by the recording unit is an ink, but the recording liquid used for a wide variety of applications can be targeted. The components of the ink are not particularly limited, but the ink used in the present embodiment is an aqueous pigment ink containing a pigment which is a coloring material, water, and a resin.

<Image recording device>
FIG. 1 is a front view schematically showing an image recording apparatus 1 according to an embodiment of the present invention. The image recording apparatus 1 is a sheet-fed ink jet printer that manufactures a recorded matter P2 by transferring an ink image from a transfer body 2 to a recording medium P1. The image recording device 1 includes a recording device 1A and a conveyance device 1B. The recording apparatus 1 </ b> A includes a recording unit 3, a transfer unit 4, peripheral units 5 </ b> A to 5 </ b> D, and a supply unit 6. The X direction, the Y direction, and the Z direction respectively indicate the width direction (full length direction), the depth direction, and the height direction of the image recording apparatus 1. The recording medium P1 is transported in the X direction.

<Recording unit>
The recording unit 3 includes a plurality of recording heads 30 and a carriage 31 that supports the plurality of recording heads 30. The plurality of recording heads 30 are radially arranged around the transfer body 2 which rotates around the central axis. The recording head 30 discharges liquid ink to the transfer body 2 and forms an ink image of a recording image on the transfer body 2. Each recording head 30 is a full line head extending in the Y direction, and a plurality of nozzles are arranged in a range covering the width of the image recording area of the recording medium of the maximum size that can be used. The recording head 30 has an ink nozzle surface on the lower surface of which a plurality of nozzles are opened. The ink nozzle surface is opposed to the outer peripheral surface of the transfer body 2 via a minute gap (for example, several mm). The gap between the ink nozzle surface and the outer peripheral surface of the transfer member 2 is accurately maintained by the carriage 31. The carriage 31 is displaceably supported in the Y direction by a pair of guide members RL via slide portions 32 provided on both sides in the X direction. The pair of guide members RL are rail members provided on both sides of the carriage 31 in the X direction and extending in the Y direction. Although not shown, a recovery unit is provided on the side of the recording unit 3 in the Y direction. The recording unit 3 can be moved to the recovery unit by the guidance of the guide member RL.

  Each nozzle is combined with an ink ejection element (not shown). As the ink ejection element, for example, an element that ejects ink by causing film boiling in the ink with an electro-thermal converter to form bubbles, an element that ejects ink by an electro-mechanical converter, and ink using electrostatic charge And the like. When high-speed and high-density recording is performed, an ink ejection element using an electro-thermal converter can be used.

  In the present embodiment, nine recording heads 30 are provided. Each recording head 30 ejects different types of ink, such as yellow, magenta, cyan, and black. Any of the recording heads 30 may eject ink (for example, clear ink) containing no coloring material. One recording head 30 ejects one type of ink, but one recording head 30 may eject a plurality of types of ink. The recording head 30 on the most downstream side (the rightmost side in FIG. 1) in the printing process ejects a transfer rate improving agent. The transfer rate improver is a transparent liquid containing no coloring material, and is discharged onto the surface of the image of the ink formed on the transfer member 2 to improve the transfer rate.

<Transfer unit>
The transfer unit 4 includes a transfer body 41 and an impression cylinder 42. The transfer body 41 and the impression cylinder 42 are rotating bodies that rotate around a rotation axis extending in the Y direction, and have a cylindrical outer peripheral surface. In FIG. 1, the arrows shown inside the transfer body 41 and the impression cylinder 42 indicate the circulation direction or rotation direction of these, and the transfer body 41 rotates clockwise and the impression cylinder 42 rotates counterclockwise. That is, the transfer body 41 and the impression cylinder 42 rotate in opposite directions.

  The transfer body 41 is a support that supports the transfer body 2 on the outer peripheral surface thereof. The transfer body 2 is provided on the outer peripheral surface of the transfer body 41 continuously or intermittently in the circumferential direction. When continuously provided, the transfer body 2 is formed in an endless belt shape. When provided intermittently, the transfer body 2 is formed of a plurality of strip-like segments with an end, and the plurality of segments are arranged on the outer peripheral surface of the transfer body 41 in an arc at an equal pitch. The transfer body 2 is composed of a single layer, but may be composed of a laminate of a plurality of layers, for example, three layers of a surface layer, a compression layer, and an elastic layer located between the surface layer and the compression layer. Good. The surface layer is the outermost layer having an image recording surface on which an ink image is formed. The compression layer has deformation absorption performance, can disperse local pressure fluctuation, and can maintain transferability even at high speed recording.

  By the rotation of the transfer body 41, the transfer body 2 moves circularly on a circular orbit. The transfer body 2 is divided into a discharge pretreatment area R1, a discharge area R2, a discharge post processing area R3 and R4, a transfer area R5, and a transfer post processing area R6 according to the rotational phase of the transfer body 41. The transfer body 2 passes cyclically through these regions. According to the clock face of the watch, in FIG. 1, the pre-ejection processing area R1 is approximately at 10 o'clock position, the ejection area R2 is approximately between 11 o'clock and 1 o'clock, and the post-ejection processing area R3 is approximately 2 o'clock , And the post-discharge post-processing area R4 is approximately at 4 o'clock. The transfer region R5 is at a position of about 6 o'clock, and the post-transfer treatment region R6 is a region of about 8 o'clock.

  In the ejection pretreatment region R1, pretreatment of the transfer body 2 by the peripheral unit 5A is performed before ejection of the ink by the recording unit 3. Specifically, the reaction liquid is applied to the outer peripheral surface of the transfer body 2. In the ejection region R2, the recording unit 3 ejects the ink to the outer peripheral surface of the transfer body 2, and an ink image is formed on the outer peripheral surface of the transfer body 2. In the post-discharge post-processing areas R3 and R4, the process for the ink image is performed after the discharge of the ink and before the transfer of the ink image. In the post-discharge processing region R3, processing by the peripheral unit 5B is performed, and in the discharge post-processing region R4, processing by the peripheral unit 5C is performed. In the transfer area R5, the ink image on the transfer body 2 is transferred to the recording medium P1 by the transfer unit 4. In the post-transfer processing region R6, the peripheral unit 5D performs post-processing on the transfer body 2 after transfer of the ink image. Although the regions R1 to R6 have a certain angular range. The angular range of the regions R1 and R3 to R6 is smaller than the angular range of the ejection region R2.

  The outer peripheral surface of the impression cylinder 42 is in pressure contact with the transfer member 2. The impression cylinder 42 forms a nip portion 11 for nipping the recording medium P 1 to be conveyed with the transfer body 41, and transfers the ink image formed on the outer peripheral surface of the transfer body 2 to the recording medium at the nip portion 11. . That is, when the recording medium P1 passes the nip portion 11 formed by the impression cylinder 42 and the transfer member 2 while being conveyed, the ink image on the transfer member 2 is transferred onto the surface facing the impression cylinder 42 . At least one grip mechanism (not shown) for holding the leading end of the recording medium P1 is provided on the outer peripheral surface of the impression cylinder 42. A plurality of gripping mechanisms may be provided separately in the circumferential direction of the impression cylinder 42.

<Peripheral unit>
Peripheral units 5A to 5D are arranged around the transfer body 2. In the case of the present embodiment, the peripheral units 5A to 5D are, in order, the reaction liquid application unit 5A, the absorption unit 5B, the heating unit 5C, and the cleaning unit 5D. The reaction liquid application unit 5A is located in the front stage of the recording unit 3 with respect to the direction in which the transfer body 2 rotates.

The reaction liquid applying unit 5 </ b> A applies the reaction liquid onto the transfer body 2 before the ink is ejected by the recording unit 3. The reaction liquid is a liquid containing components that increase the viscosity of the ink. To increase the viscosity of the ink, the coloring material, resin, etc. constituting the ink chemically react or physically adsorb by coming into contact with the component that increases the viscosity of the ink, whereby the viscosity of the ink is thereby obtained. An increase in the Not only increase in viscosity of the entire ink can be recognized as increase in viscosity of the ink, but also increase in viscosity locally due to aggregation of a part of components constituting the ink, such as color material and resin. included. The reaction solution is preferably applied to a film thickness of about 0.7 to 1.4 μm. Therefore, the reaction liquid deposition unit 5A includes a film thickness detector 12 that detects the film thickness of the reaction liquid applied to the transfer member 2. Although the detection method of a film thickness is not specifically limited, For example, the following method is employable.
-A method in which a reaction liquid is irradiated with light from a light source, and a reflected light of the irradiated light is detected by a detection unit, and then a detected electric signal is acquired as image data to detect a film thickness of the reaction liquid.
-A method of detecting the difference in the optical path between light reflected from the upper surface of the film and light reflected from the lower surface of the film by detecting light from a white light source and detecting the film thickness of the reaction solution.
There are no particular restrictions on the component that makes the ink highly viscous, such as metal ions and polymer flocculants, but substances that cause the pH change of the ink to coagulate the coloring material in the ink can be used, and the organic acid It can be used. As a reaction liquid application mechanism, for example, a roller, a recording head, a die coating apparatus (die coater), a blade coating apparatus (blade coater) and the like can be mentioned. If the reaction liquid is applied to the transfer body 2 before discharging the ink to the transfer body 2, the ink that has reached the transfer body 2 can be fixed immediately. This makes it possible to suppress bleeding where adjacent inks mix.

  The absorbing unit 5B absorbs part of the liquid component from the ink image on the transfer body 2 before transferring the ink image. By reducing the liquid component of the ink image, it is possible to suppress bleeding and the like of the image recorded on the recording medium P1. If the reduction of the liquid component is explained from a different viewpoint, it can also be expressed as concentration of the ink constituting the ink image on the transfer body 2. To concentrate the ink means to decrease the liquid component contained in the ink and to increase the content ratio to the solid component such as the coloring material and the resin contained in the ink.

  The absorbing unit 5B includes, for example, a liquid absorbing member that contacts the ink image to reduce the amount of the liquid component of the ink image. The liquid absorbing member may be formed on the outer peripheral surface of the roller, or the liquid absorbing member may be formed in an endless sheet shape and may be cyclically traveled by roller conveyance. In order to protect the ink image, the liquid absorbing member may be moved in synchronization with the transfer body 2 with the moving speed of the liquid absorbing member being the same as the circumferential speed of the transfer body 2.

  The liquid absorbing member may include a porous body in contact with the ink image. The pore diameter of the porous material on the surface in contact with the ink image may be 10 μm or less in order to suppress the adhesion of the solid ink content to the liquid absorbing member. Here, the pore diameter indicates the average diameter and can be measured by a known means such as mercury porosimetry, nitrogen adsorption, SEM image observation and the like. The liquid component is not particularly limited as long as it does not have a fixed shape, is fluid, and has a substantially fixed volume. For example, water, an organic solvent and the like contained in the ink and the reaction liquid may be mentioned as the liquid component.

  The heating unit 5C heats the ink image on the transfer body 2 before transferring the ink image. By heating the ink image, the resin in the ink image is melted and transferability to the recording medium P1 is improved. By heating the ink image at a high temperature, it is also possible to vaporize and remove a part of the liquid component of the ink image remaining after passing through the absorbing unit 5B. The heating temperature can be equal to or higher than the minimum film forming temperature (MFT) of the resin. The MFT can be measured by a generally known method, for example, each device conforming to JIS K 6828-2: 2003 or ISO 2115: 1996. From the viewpoint of transferability and image fastness, heating may be performed at a temperature 10 ° C. or more higher than MFT, and may be further heated 20 ° C. or more. The heating unit 5C can use, for example, various known lamps such as an infrared lamp, a warm air fan, and the like. An infrared heater can be used in terms of heating efficiency.

  The cleaning unit 5D cleans the outer peripheral surface of the transfer body 2 after transfer. The cleaning unit 5 D removes ink remaining on the transfer body 2, dust on the transfer body 2, and the like. The cleaning unit 5D is, for example, a known method in which a porous member is brought into contact with the outer peripheral surface of the transfer body 2, a method in which the outer peripheral surface of the transfer body 2 is rubbed with a brush, or a system in which the outer peripheral surface of the transfer body 2 is scraped with a blade. The scheme can be used as appropriate. In addition, a cleaning member used for cleaning may have a known shape such as a roller shape or a web shape.

  Any of the reaction liquid application unit 5A, the absorption unit 5B, the heating unit 5C, and the cleaning unit 5D may have a cooling function of the transfer body 2. Alternatively, a cooling unit may be added. The temperature of the transfer body 2 may rise due to the heat of the heating unit 5C. If the ink image exceeds the boiling point of water which is the main solvent of the ink after the recording unit 3 discharges the ink onto the transfer body 2, the absorption performance of the liquid component by the absorption unit 5B may be lowered. By cooling the transfer body 2 so that the ejected ink is maintained below the boiling point of water, the absorption performance of the liquid component can be maintained. The cooling unit may be a blower mechanism for blowing air to the transfer body 2 or a mechanism for bringing a member (for example, a roller) into contact with the transfer body 2 and cooling the member by air cooling or water cooling. The cooling unit may be a mechanism for cooling the cleaning member of the cleaning unit 5D. The cooling timing may be a period after transfer and before application of the reaction liquid.

<Supply unit>
The supply unit 6 supplies the ink to each recording head 30 of the recording unit 3. The supply unit 6 includes a reservoir TK that stores ink for each type of ink. The reservoirs TK and the recording heads 30 communicate with each other through the flow path 6 a, and the ink is supplied from the reservoirs TK to the recording heads 30. The flow path 6a may be a flow path for circulating the ink between the reservoir TK and the recording head 30, and the supply unit 6 may be provided with a pump or the like for circulating the ink.

<Transporting device>
The conveyance device 1B is a device that feeds the recording medium P1 to the transfer unit 4 and discharges the recording material P2 on which the ink image has been transferred from the transfer unit 4. The transport device 1B includes a feeding unit 7, a plurality of transport cylinders 8, 8a, two sprockets 8b, a chain 8c, and a recovery unit 8d. In FIG. 1, the arrow on the inside of each element of the conveyance device 1B indicates the circulation direction of the element, and the arrow on the outside indicates the conveyance path of the recording medium P1 or the recording material P2. The recording medium P1 is conveyed from the feeding unit 7 to the transfer unit 4, and the recording material P2 is conveyed from the transfer unit 4 to the collection unit 8d. The feed unit 7 side may be referred to as the upstream side in the transport direction, and the recovery unit 8 d side may be referred to as the downstream side.

  The feeding unit 7 includes a loading unit on which a plurality of recording media P1 are loaded, and also includes a feeding mechanism for feeding the recording media P1 one by one from the loading unit to the uppermost stream transport cylinder 8. Each of the transport cylinders 8 and 8a is a rotary body that rotates around a rotation axis in the Y direction, and has a cylindrical outer peripheral surface. At least one grip mechanism for holding the leading end of the recording medium P1 (or the recording material P2) is provided on the outer peripheral surface of each of the transport cylinders 8 and 8a. The gripping operation and the releasing operation of each gripping mechanism are controlled so that the recording medium P1 is transferred between the adjacent transport cylinders.

  The two transport cylinders 8a are transport cylinders for reversing the recording medium P1. When the recording medium P1 is recorded on both sides, after transfer to the outer peripheral surface, the recording medium P1 is transferred from the impression cylinder 42 to the transfer cylinder 8a without passing the recording medium P1 to the transfer cylinder 8 adjacent downstream. The recording medium P1 is turned upside down via the two transfer cylinders 8a, and is transferred to the pressure cylinder 42 again via the transfer cylinder 8 on the upstream side of the pressure cylinder 42. As a result, the back surface of the recording medium P1 faces the transfer body 41, and the ink image is transferred to the back surface. The chain 8c is wound between two sprockets 8b. One of the two sprockets 8b is a drive sprocket and the other is a driven sprocket. The rotation of the drive sprocket causes the chain 8c to travel cyclically. The chain 8c is provided with a plurality of gripping mechanisms spaced apart in the longitudinal direction. The grip mechanism grips the end of the recorded matter P2. The recording material P2 is delivered from the transport cylinder 8 located at the downstream end to the grip mechanism of the chain 8c, and the recording material P2 gripped by the grip mechanism is transported to the recovery unit 8d by traveling of the chain 8c, and the gripping is released. As a result, the recorded matter P2 is loaded in the recovery unit 8d.

<Post-processing unit>
Post-processing units 10A and 10B are provided in the transport device 1B. The post-processing units 10A and 10B are disposed downstream of the transfer unit 4 and perform post-processing on the recorded matter P2. The post-processing unit 10A performs processing on the surface of the recording material P2, and the post-processing unit 10B performs processing on the back surface of the recording material P2. Examples of the contents of the process include a coating for protecting an image, glossing, and the like on the image recording surface of the recorded matter P2. Examples of the content of the coating include application of a liquid, welding of a recording medium, lamination, and the like.

<Inspection unit>
Inspection units 9A and 9B are provided in the transport apparatus 1B. The inspection units 9A and 9B are disposed downstream of the transfer unit 4 and are mechanisms for inspecting the recorded matter P2. The inspection unit 9A is a photographing device for photographing an image recorded in the recording material P2, and includes, for example, a photographing element such as a CCD sensor or a CMOS sensor. The inspection unit 9A captures a recorded image during the recording operation which is continuously performed. Based on the image photographed by the inspection unit 9A, it is possible to confirm the temporal change of the color tone or the like of the recorded image, and to judge whether the image data or the recorded data can be corrected. In the inspection unit 9A, a photographing range is set on the outer peripheral surface of the impression cylinder 42, and the recording image immediately after transfer is arranged so as to be partially photographed. Inspection of all the recorded images may be performed by the inspection unit 9A, or inspection may be performed for each predetermined number. The inspection unit 9B is also a photographing device for photographing an image recorded in the recording material P2, and includes, for example, a photographing element such as a CCD sensor or a CMOS sensor. The inspection unit 9B captures a recorded image in the test recording operation. The inspection unit 9B can photograph the entire recording image, and can perform basic settings of various corrections on the recording data based on the image photographed by the inspection unit 9B. The inspection unit 9B is disposed at a position where the recording material P2 conveyed by the chain 8c is photographed. When the recorded image is photographed by the inspection unit 9B, the traveling of the chain 8c is temporarily stopped and the whole is photographed. The inspection unit 9B may be a scanner that scans the recording material P2.

<Control unit>
Next, the control unit of the image recording apparatus 1 will be described. 2 and 3 are block diagrams of the control unit 13 of the image recording apparatus 1. The control unit 13 is communicably connected to the host device (DFE) HC2, and the host device HC2 is communicably connected to the host device HC1.

  In the host device HC1, original data as a source of a recorded image is generated or stored. The manuscript data is generated, for example, in the form of an electronic file such as a document file or an image file. The document data is transmitted to the host device HC2, and the host device HC2 converts the received document data into a data format usable by the control unit 13 (for example, RGB data representing an image in RGB). The converted data is transmitted as image data from the higher-level device HC2 to the control unit 13, and the control unit 13 starts the recording operation based on the received image data.

  The control unit 13 is roughly divided into a main controller 13A and an engine controller 13B. The main controller 13A includes a processing unit 131, a storage unit 132, an operation unit 133, an image processing unit 134, a communication I / F (interface) 135, a buffer 136, and a communication I / F 137. The processing unit 131 is a processor such as a CPU, executes a program stored in the storage unit 132, and controls the entire main controller 13A. The storage unit 132 is a storage device such as a RAM, a ROM, a hard disk, an SSD, etc., stores programs executed by the CPU 131 and data, and provides the CPU 131 with a work area. The operation unit 133 is, for example, an input device such as a touch panel, a keyboard, or a mouse, and receives an instruction of the user. The image processing unit 134 is an electronic circuit having, for example, an image processing processor. The communication I / F 135 communicates with the host device HC2. The buffer 136 is, for example, a RAM, a hard disk or an SSD. The communication I / F 137 communicates with the engine controller 13B.

  The broken arrows in FIG. 2 illustrate the flow of processing of the image data. Image data received from the host device HC2 via the communication IF 135 is stored in the buffer 136. The image processing unit 134 reads the image data from the buffer 136, performs predetermined image processing on the read image data, and stores the image data in the buffer 136 again. The image data after image processing stored in the buffer 136 is transmitted from the communication I / F 137 to the engine controller 13B as print data used by the print engine. An image offset register is provided to determine the discharge start position on the discharge area R2. The print timing of the print data in the buffer 136 is offset by the image offset register to control the print position.

  As shown in FIG. 3, the engine controller 13B includes control units 14 and 15A to 15E, and performs acquisition and drive control of detection results of the sensor group and the actuator group 16 included in the image recording device 1. Each of these control units includes a processor such as a CPU, a storage device such as a RAM or a ROM, and an interface with an external device. The division of the control unit is an example, and a part of the control may be executed by a plurality of further divided control units, or conversely, the control contents of one control unit may be integrated by integrating a plurality of control units. It may be configured to be performed by one control unit.

  The engine control unit 14 controls the entire engine controller 13B. The recording control unit 15A converts the recording data received from the main controller 13A into a data format such as raster data, which is suitable for driving the recording head 30. The recording control unit 15A performs discharge control of each recording head 30. The transfer control unit 15B controls the reaction liquid application unit 5A, controls the absorption unit 5B, controls the heating unit 5C, and controls the cleaning unit 5D. The reliability control unit 15C performs control of the supply unit 6, control of the recovery unit, and control of a drive mechanism for moving the recording unit 3 between the ejection position and the recovery position. The transport control unit 15D controls the transport device 1B. The inspection control unit 15E controls the inspection units 9A and 9B. The sensor group and the actuator group 16 include a sensor group that detects the position and velocity of the movable portion, a sensor that detects a temperature, and a sensor group such as an imaging element. The actuator group includes a motor, an electromagnetic solenoid, an electromagnetic valve, and the like.

<Recording operation>
FIG. 4 is a view schematically showing an example of the recording operation. The following steps are cyclically performed while the transfer body 41 and the impression cylinder 42 are rotated. As shown in the state ST1, first, the reaction liquid application unit 5A applies the reaction liquid L onto the transfer member 2. The portion of the transfer body 2 to which the reaction liquid L is applied moves as the transfer body 41 rotates. When the portion to which the reaction liquid L is applied reaches under the recording head 30, the ink is discharged from the recording head 30 to the transfer body 2 as shown in the state ST2. Thus, the ink image IM is formed. At this time, the ejected ink mixes with the reaction liquid L on the transfer member 2 to promote aggregation of the color material. The ejected ink is supplied from the storage portion TK of the supply unit 6 to the recording head 30.

  The ink image IM on the transfer body 2 moves as the transfer body 2 rotates. When the ink image IM reaches the absorbing unit 5B, the liquid component is absorbed from the ink image IM by the absorbing unit 5B as shown in the state ST3. When the ink image IM reaches the heating unit 5C, as shown in the state ST4, the ink image IM is heated by the heating unit 5C, the liquid component in the ink image IM evaporates, and the resin in the ink image IM melts. IM is film-formed. The recording medium P1 is conveyed by the conveyance device 1B in synchronization with the formation of the ink image IM.

  As shown in the state ST5, the ink image IM and the recording medium P1 reach the nip portion 11 of the transfer body 2 and the impression cylinder 42, the ink image IM is transferred to the recording medium P1, and the recording material P2 is manufactured. . After passing through the nip portion 11, the image recorded on the recording material P2 is photographed by the inspection unit 9A, and the recorded image is inspected. The recorded matter P2 is conveyed by the conveyance device 1B to the collection unit 8d.

  When the ink image IM is formed on the transfer body 2 and reaches the cleaning unit 5D, it is cleaned by the cleaning unit 5D as shown in the state ST6. After cleaning, the transfer body 2 is rotated once, and the transfer of the ink image to the recording medium P1 is repeated in the same procedure. In the above description, in order to facilitate understanding, it has been described that transfer of the ink image IM to one recording medium P1 is performed in one rotation of the transfer body 2; The transfer of the ink image IM to the recording medium P1 can be performed continuously.

  FIG. 5 is a partial development view of the transfer body 2; a region to which the reaction liquid is applied, that is, a formation region of a film of the reaction liquid (hereinafter referred to as the application region 93) (Referred to as a region 92). The print area 92 corresponds to an area where printing is to be performed on the recording medium. In the present embodiment, recording on a B2 size recording medium is possible, and the reaction liquid is applied to the B2 size application region 93. Further, in the present embodiment, the size of the printing area 92, that is, the size of the recorded matter is A3 size smaller than this, and the printing area 92 is set at the upper right portion of the application area 93. The region where the unevenness of the film thickness of the reaction solution is large (specifically, the region where the film thickness maximum difference described below exceeds the third allowable value, hereinafter referred to as the application unevenness region 122) Is assumed to be in the lower left part of. The area scheduled to form the ink image is not limited to the upper right portion of the application area 93, and is assigned in advance to a predetermined area of the application area 93. As described below, the ink image may actually be formed in the area where the ink image is to be formed, or may be formed in another area of the application area 93, or the ink image is formed in a row. In some cases it is impossible.

  FIG. 6 shows an example of a flowchart for executing the image recording method of the present invention. This flowchart is executed by a program stored in the engine controller 13B (control unit). A series of printing processes are started by the printing instruction from the main controller 13A upstream of the engine controller 13B (step S101). First, the reaction liquid is applied to the transfer body 2 and a film of the reaction liquid is formed on the outer peripheral surface of the transfer body 2 (step S102). Next, an allowable value (hereinafter referred to as a third allowable value) of the difference between the maximum film thickness and the minimum film thickness of the reaction solution (hereinafter referred to as the film thickness maximum difference) is set (step S103). Since the film thickness of the reaction solution can be restated as the concentration of the reaction solution, the third tolerance can also be said to be the tolerance of the difference between the maximum concentration and the minimum concentration of the reaction solution. The third allowable value differs depending on the recording medium, and is 0.5 μm in one example, and 0.3 μm in another example. The third allowable value can be set to a large value for a recording medium in which the density difference of the reaction solution is not noticeable, and the third tolerance value is set to a small value for a recording medium in which the density difference of the reaction solution is noticeable. The third allowable value can be set more finely in consideration of not only the type of recording medium but also the environmental temperature and the environmental humidity. The third allowable value is stored in advance in the storage unit 132 for each recording medium. The type of recording medium may be input by the user to the input unit such as the operation unit 133 or may be automatically detected by a mechanical detection unit.

  Next, the film thickness of the film of the reaction liquid in the application region 93 is detected in the horizontal direction and the vertical direction (step S104). Specifically, the film thickness of the film of the reaction liquid is parallel to the circumferential direction of the transfer body 2 by a plurality of first lines 120 a to 120 f parallel to the rotational axis direction of the transfer body 2 by the film thickness detector 12. Are measured along the plurality of second lines 121a to 121d. FIG. 7 shows an example of the film thickness detected along these lines, that is, an example of the output value of the film thickness detector 12. Next, the film thickness on the first line and the film thickness on the second line are added up at the intersections of the first lines 120a to 120f and the second lines 121a to 121d (step S105). . That is, the output values on the first lines 120a to 120f at each intersection point and the output values on the second lines 121a to 121d are summed. Thus, the total film thickness values at the lattice points G11 to G14, G21 to G24, G31 to G34, G41 to G44, G51 to G54, and G61 to G64 shown in FIG. The dimensional distribution can be determined. In addition, since the film thickness total value is approximately twice of the measurement value of the film thickness detector 12, a value obtained by dividing the total value by 2 may be used as the film thickness at each grid point. When the measurement values of the first line 120a to 120f and the measurement values of the second lines 121a to 121d are applied alone, the error of the film thickness detector 12 may not be able to make an accurate measurement, but two outputs The accuracy of the film thickness measurement can be enhanced by summing. Next, the difference in film thickness at each lattice point is obtained from the film thickness total value (step S106).

  Next, a subroutine for detecting unevenness in the film thickness of the reaction liquid is called, and it is determined whether printing is possible (step S107). FIG. 8 shows a flowchart of the unevenness detection subroutine called at step S107. First, unevenness detection is started (step S201), and then the maximum film thickness and the minimum film thickness in the application region 93, and the film thickness maximum difference are checked. The maximum film thickness is then compared to a first tolerance and the minimum film thickness is compared to a second tolerance. The first allowable value is the maximum allowable film thickness of the reaction solution, and is set to, for example, 1.4 μm. The second allowable value is the minimum allowable film thickness of the reaction solution, and is set to, for example, 0.7 μm. The first tolerance value and the second tolerance value are stored in advance in the storage unit 132, and may be different for each type of recording medium. When the maximum film thickness exceeds the first allowable value or when the minimum film thickness falls below the second allowable value, it is determined that printing is impossible, and an error signal is returned (step S211).

  If the maximum film thickness is less than or equal to the first tolerance and the minimum film thickness is greater than or equal to the second tolerance, the film thickness maximum difference is compared with the third tolerance (step S204). The third allowable value is preset for each type of recording medium as described above. If the film thickness maximum difference is equal to or less than the third allowable value, it is determined that printing is possible (step S210). If the film thickness maximum difference exceeds the third allowable value, the relationship between the size of the application area 93 and the size of the printing area 92 is examined. For example, when the application area 93 is B2 size and the printing area 92 is also B2 size, it is determined that the application area 93 and the printing area 92 are the same size. When the application area 93 is B2 size and the printing area 92 is A3 size, it is determined that the printing area 92 is smaller than the application area 93. When the print area 92 has the same size as the application area 93, it is determined that printing is impossible (step S211). If the print area 92 is smaller than the application area 93, the film thickness maximum difference in the current print area 92 is checked (step S206). Since the print area 92 is smaller than the application area 93, even if the film thickness maximum difference in the application area 93 exceeds the third allowable value, the film thickness maximum difference in the print area 92 can be equal to or less than the third allowable value. It is because there is sex. If the film thickness maximum difference is equal to or less than the third allowable value, it is determined that printing is possible (step S210).

  When the film thickness maximum difference exceeds the third allowable value, it is searched whether printing is possible in another area different from the printing area 92 of the application area 93 (step S208). Specifically, the print area 92 is shifted little by little in the X direction and the Y direction, the film thickness maximum difference in each print area is determined, and compared with the third allowable value. If an area where the film thickness maximum difference is equal to or less than the third allowable value is found, it is determined that printing is possible (step S210), and the area is set as a new print area 92. Alternatively, even after a region where the film thickness maximum difference is equal to or less than the third allowable value is found, the printing region 92 is gradually shifted in the X and Y directions, and the entire printing region 93 is scanned with the printing region 92 An area where the thickness maximum difference is minimized may be set as a new print area 92. The latter method requires a long time for processing, but can produce recorded matter with excellent image quality. On the other hand, if no region where the film thickness maximum difference is equal to or less than the third allowable value is found, it is determined that printing is impossible (step S211). In this way, it is determined that printing is not possible if any of the first to third allowable values is not satisfied, and printing is determined to be possible if any of the first to third allowable values is satisfied. A new print area 92 is set as necessary. When the above processing ends, the subroutine ends (step S212).

  Unevenness in the film thickness of the reaction solution may occur on the front and back sides of the transfer body 2 or on the upstream and downstream sides of the transfer body 2. In the example shown in FIG. 5, the uneven coating area exists in the area surrounded by the grid points G11, G12, G21, and G22. FIG. 7 corresponds to the uneven coating area of FIG. Since the first lines 120a to 120d are relatively flat and hardly fluctuate in film thickness, it is judged that the film thickness of the reaction solution is substantially uniform. On the other hand, in the first lines 120e and 120f, an increase in film thickness is detected in the left region 122a. This indicates that there is a large portion of the film thickness of the reaction liquid in the lower area of the application area 93. Since the second lines 121c and 121d are relatively flat and hardly fluctuate in film thickness, it is judged that the film thickness of the reaction solution is substantially uniform. On the other hand, in the second lines 121a and 121b, an increase in film thickness is detected in the region 122b on the right side. This indicates that there is a large thickness portion of the reaction solution in the right side area of the application area 93. From these facts, it is determined that the film thickness largely fluctuates in the region surrounded by the lower left grid points G11, G12, G21, and G22 of the application region 93 in FIG. 5, that is, application unevenness is made. . Therefore, the print area 92 is set at a position avoiding the area surrounded by G11, G12, G21, and G22. In another example shown in FIG. 9, the film thickness maximum difference exceeds the third allowable value in the area surrounded by the lattice points G11, G14, G23, and G21, G22, G31, G32. In the present embodiment, since the film thickness of the reaction solution can be grasped in a two-dimensional manner, not only the film thickness greatly increases at the lattice points G11, G14, and G23, but also the film thickness of the region surrounded by the lattice points Trends can also be estimated. Therefore, in the example of FIG. 9, it is determined that the film thickness maximum difference exceeds the third allowable value in the area surrounded by G21, G22, G31, and G32.

  In step S108, it is checked in the unevenness detection subroutine whether a non-printable error has occurred. If an error has not occurred, printing is started (step S109), and when printing is finished, a series of printing processes are finished (step S111). If an error occurs in step S108, an error notification is sent to the upstream main controller 13A (step S110), and the series of printing processes is completed (step S111). The process from step S103 to step S109 is performed while the transfer body 2 moves from the pre-ejection processing region R1 to the ejection region R2.

  As described above, according to the present embodiment, it is determined whether to form an ink image according to the film thickness of the reaction liquid, and it is determined whether to operate the recording unit 3 based on the determination result. This reduces the possibility of producing inferior recorded materials.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to embodiment. Hereinafter, some modifications will be described. The recording unit 3 may have only one recording head 30 instead of the plurality of recording heads 30. The recording head 30 may be a serial method in which an ink image is formed while scanning in the Y direction. The conveyance mechanism of the recording medium P1 may be a system in which the recording medium P1 is pinched and conveyed by the roller pair. In this case, the recording medium P may be a roll sheet, and the recording material P2 can be manufactured by cutting the roll sheet after transfer. The transfer body 2 is not limited to the method in which the transfer body 2 is provided on the outer peripheral surface of the transfer cylinder 41, but may be a method of forming the transfer body 2 in an endless belt shape and traveling cyclically. The program for realizing the functions described above may be supplied via a network or a storage medium instead of being stored in the storage unit of the image recording apparatus. In that case, the processor of the image recording apparatus can read and execute the program. Also, the functions described above can be implemented by a circuit (eg, an ASIC) that implements one or more functions. As a method of applying the reaction liquid, it is possible to apply a large amount of reaction liquid, and after application, the reaction liquid can be treated (cut, extended, spread, sucked, etc.) with a rubber wiper or the like. Thickness can also be optimized.

  If the unevenness of the film thickness of the reaction liquid to be applied does not change frequently, the film thickness of the reaction liquid may be confirmed at the time of regular maintenance using the image recording apparatus in the state set at the time of factory shipment. After that, when the unevenness changes frequently, the unevenness can be checked periodically by a cyclic handler or the like. Although the minimum film thickness, maximum film thickness and film thickness maximum difference of the reaction liquid, and the third allowable value are changed for each print job, the change may be reflected once for multiple jobs, It may be only when the power of the image recording apparatus is turned on, or may be every several weeks or once every several months. When the detection result of the film thickness at the lattice point is unstable, even if the maximum film thickness, the minimum film thickness and the film thickness maximum difference are calculated based on the film thickness detection result in the first line or the second line Good.

If no region where the film thickness maximum difference is equal to or less than the third allowable value is found, the following method can be taken. According to these methods, printing can be performed even when no region where the film thickness maximum difference is equal to or less than the third allowable value is found.
Printing is not judged as being impossible, and printing is carried out in an area where the film thickness maximum difference is small, preferably the area where it is minimized.
-If the image data is analyzed and there is no image data to be printed in the area where the film thickness maximum difference exceeds the third allowable value (that is, if the ink is not ejected), movement of the printing area 92 or printing impossible Print without making a decision. Specifically, it is determined whether the portion where the film thickness maximum difference exceeds the third allowable value is the portion where the ink is actually ejected. Then, when the ink is not discharged to the portion, the problem of the unevenness of the image data does not occur, and the printing can be continued. The same applies to thin images and images in which unevenness is not noticeable. If the image data includes an image area in which unevenness is noticeable and an image area in which unevenness is inconspicuous, it is also possible to assign an image area in which unevenness is inconspicuous to an area where the film thickness maximum difference exceeds the third allowable value.
-If the quality requirement of the recorded matter is not high, for example, in the case of test printing or draft printing, movement of the printing area 92 or printing impossible even if no area falling below the third allowable value is found It is also possible to continue printing without making a determination.

  If there is a print area 92 of A3 inside the application area 93 of B2, the central part is always a common area to be printed regardless of where the print area 92 is moved. In that case, the print area 92 may be set in the area having the same maximum film thickness difference as the film thickness maximum difference of the central common area. At this time, the film thickness detection points may be narrowed to five points at the center of the common area and at the four corners of the application area 93. According to this method, the film thickness detection process can be simplified.

1 Image recording device.
Reference Signs List 2 transfer body 3 recording unit 4 transfer unit 5A recording unit 14, 15A to 15E control unit 42 impression cylinder

Claims (8)

A transfer unit having a transfer body forming a nip portion and an impression cylinder, and in the nip portion, an image of the recording liquid formed on the transfer body is transferred to a recording medium;
A recording unit that discharges the recording liquid and forms an image of the recording liquid on the transfer body;
A reaction liquid application unit that forms a film of a reaction liquid that increases the viscosity of the recording liquid on the transfer member before an image of the recording liquid is formed;
A detector for detecting the film thickness of the film of the reaction liquid formed on the transfer body;
An image recording apparatus comprising: a control unit that determines whether to form an image of the recording liquid according to the film thickness and determines whether to operate the recording unit based on the determination result.   The control unit is configured such that the maximum film thickness of the reaction liquid film is equal to or less than a first allowable value, and the minimum film thickness of the reaction liquid film is equal to or greater than a second allowable value. When the difference in film thickness exceeds the third allowable value and the area scheduled to form the image is smaller than the area on the reaction liquid film, the difference in the region scheduled to form the image is smaller than the third allowable value. The image according to claim 1, wherein the recording unit is controlled to form an image of the recording liquid in the image formation planned area of the image when the value is less than the third allowable value. Recording device.   When the difference in the image formation scheduled area exceeds the third allowable value, the control unit searches another area where the difference is equal to or less than the third allowable value, and the other area The image recording apparatus according to claim 2, wherein the recording unit is controlled to form an image of the recording liquid in the other area when it is found.   The image recording apparatus according to claim 3, wherein the control unit controls the recording unit to form an image of the recording liquid in an area where the difference is minimum.   The control unit is configured such that the maximum film thickness of the reaction liquid film is equal to or less than a first allowable value, and the minimum film thickness of the reaction liquid film is equal to or greater than a second allowable value. When the film thickness difference exceeds the third allowable value, it is determined whether the portion where the difference exceeds the third allowable value is the portion to which the recording liquid is ejected, and the difference is the third value. The image according to claim 1, wherein the recording unit is controlled to form an image of the recording liquid in the image formation scheduled area when the portion exceeding the allowable value of 3 is not a portion to which the recording liquid is discharged. Recording device. A storage unit that stores the third allowable value for each type of recording medium;
An input means or detection means of the type of recording medium;
The image according to any one of claims 2 to 5, wherein the control unit compares the third tolerance value corresponding to the recording medium input from the input unit or detected by the detection unit with the difference. Recording device.   The detector measures the film thickness along a plurality of first lines parallel to the rotational axis direction of the transfer member and a plurality of second lines parallel to the circumferential direction, and The two-dimensional distribution of the film thickness is detected by adding up the film thickness on the first line and the film thickness on the second line at the intersection of each second line. The image recording apparatus according to any one of the above. A recording method of recording on a recording medium by transferring an image of a recording liquid formed on a transfer body by a recording unit onto a recording medium,
Forming a film of a reaction liquid on the transfer body to increase the viscosity of the recording liquid;
Detecting a film thickness of the film of the reaction solution formed on the transfer body;
And determining whether to form an image of the recording liquid according to the film thickness, and determining whether to operate the recording unit based on the determination result.

Images